Electronic devices including integrated chips (ICs) undergo various forms of testing during the development of such a device as well as a part of the manufacturing process for such a device. Such developmental testing can include testing to determine the suitability or capability of the device to operate in the intended manner under expected operating conditions such as a range of environmental temperature conditions. Such manufacturing related testing can include testing to determine operational characteristics of the device, the acceptability of same and to verify operational capability under differing temperature conditions.
Because such electronic devices are used together with other electrical/electronic components to form a specific operational device, it is desirous to determine the functional acceptability of a given electrical/electronic device/component before it is combined with other components to minimize the potential for the failure of the specific operational device. For example, one would want to verify the operational capability of an IC for use in an engine control module (ECU) before the ECU is assembled to minimize the number of ECUs that could be rejected for a defective IC. Such testing also would be done in the case where one was developing an electronic device/component to determine its acceptability for the intended use.
As indicated above such testing can include controlling temperature conditions of the electronic device to cover the expected or design environmental range of temperatures such as for developmental testing, a range of temperatures for manufacturing testing and a design operational temperature for determining operational characteristics of the electronic device. For example, some integrated chips are provided with some form of cooling (e.g., fan) to dissipate the heat energy being developed by the IC and/or other circuitry so the IC is maintained at or below a specific temperature. Thus, testing at the specific temperature would be suitable for determining operational characteristics.
Consequently various devices and/or methods have been developed to control the temperature of an electronic device such as an IC to simulate design environmental temperature conditions for the electronic device or IC. One technique and related devices involves the use of a thermoelectric controller (TEC) or TEC module which embodies the Peltier effect and which can be used to control over a range of temperatures. More specifically, a TEC module has been conventionally used with a coolant plate to provide this wide temperature range. However, the use of a TEC necessarily limits the maximum thermal transfer capability as well as being prone to failure. Moreover, as the DC flow in the TEC needs to be switched to switch the TEC between cooling and heating, a time delay results between the heating and cooling phases which time delay necessarily means lengthening of testing times.
There is found in U.S. Pat. No. 5,821,505 a temperature control system that comprises an electric heater that has a first face which makes contact with an electronic device, and a second face which is opposite the first face; a heat sink, coupled to the second face of the heater, which absorbs heat from the electronic device through the heater's second face; and a temperature sensor, coupled to the electronic device which senses the device temperature Td. A control circuit is coupled to the device temperature sensor and to the heater. It decreases the power to the heater when the sensed temperature of the electronic device is above the set point, and vice-versa. When the heater temperature Th is less than Td, then heat flows from the electronic device through the heater to the heat sink; and the rate of heat flow increases as Td-Th increases. When Th is more than Td, then heat flows to the electronic device from the heater; and the rate of heat flow increases as Th-Td increases
It thus would be desirable to provide a new thermal control unit or device and methods related thereto that can control a wide temperature range without using a TEC module. It would be particularly desirable to provide such a device and method that would embody a thermal clutch mechanism that would allow selective thermal coupling of a cooling device to a device under test (DUT) thereby allowing for cooling of the DUT and to decouple the cooling device from the DUT when the DUT is to be in a heating mode, thereby allowing a full temperature range during testing of the DUT. Such collection devices preferably would be no more complex construction as prior art devices and be significantly more costly than prior art devices. Also such methods would not require users to be significantly more skilled that conventional methods or for those utilizing prior art devices.